Australian researchers discover a method for optimising stem cell treatment in the brain
Earlier this year, researchers at the University of Melbourne and the Australian National University published their work in Nature communications which showed that stem cell treatment can be optimised with a certain type of hydrogel. Injecting stem cells using this hydrogel could improve survival and growth of new cells in damaged tissue.
Neurodegenerative disorders such as Parkinson’s and Alzheimer’s disease are characterised by the loss of function and structure of cells. By 2040, the World Health Organization predicts that neurodegenerative diseases will become the second leading cause of death in the world, overtaking cancer. Given that there is currently no cure for these diseases, stem cell approaches are being widely researched as a potential therapeutic strategy to restore or replace tissue loss - the work of Wang and her colleagues may have brought research one step closer to this goal.
Temporary bloodstream
When transporting stem cells to a lesion in the central nervous system, the process and environment need to meet certain metabolical needs in order for the new cells to survive and grow. The delivery method therefore needs to be carefully curated to deliver both stem cells and oxygen to the site. For this purpose, the Australian researchers engineered a water-based gel with myoglobin, a naturally occurring oxygen-binding protein found in cardiac and skeletal muscle. Hereby, the engineered hydrogel functions as a temporary ‘bloodstream’ before the new cell tissue has developed its own blood vessel network - a process called angiogenesis and vascularisation. They found that their method promoted better survival and growth of stem cells in mice.
Given that myoglobin is a compound that occurs in different species of vertebrates, the researchers assessed whether different types of myoglobin would lead to different rates of efficacy of cell transplantation. They investigated different variants of myoglobin taken from the sperm whale and found that so-called ‘high-affinity’ sperm whale myoglobin leads to the most optimal results. Whereas the ‘low-affinity’ whale myoglobin released oxygen very quickly due to low binding, the ‘high-affinity’ variant only released oxygen when the physiological environment became low in oxygen. By this slower discharge of oxygen, more stem cells survived and more cell differentiation and integration could take place.
Application in the human central nervous system
The results from this research work have currently only been reported in mice, yet it provides hope for possible applications for neurodegenerative disease in humans. Besides cell transplantation, the method could have wider applications such as organ-on-a-chip research (recreating natural human cell physiology) and drug and gene delivery. The researchers report that they did not find any adverse effects of the technology, such as increased immune response, but this proof of concept needs to be further investigated in future research.